This invention relates to distance measuring devices.
It is known to provide a so called active type distance detecting device in which a light projector and a light receptor are arranged in spaced relation by a predetermined base line distance so that while a target area is scanned by light projected from the light projector, the reflected light from an object in the target area is received by the light receptor whose electrical output signal is processed to detect a peak value indicative of a distance from the device to the object.
Such device, however, has a disadvantage that the reflected light from the object being scanned includes light components emanating from the outside of the light projector, such as ambient light, which serves as a noise, so that it is difficult to detect the peak. Another disadvantage is that the electrical signal produced from the light receptor, when being passed through the electrical circuit that follows, suffers from noise with the resultant peak being made ambiguous.
To achieve a higher accuracy of distance measurement, such influence of noise must be reduced. In this sense, the sharper the point of peak of the electrical signal, the better the result.